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Rename model methods action_use/free to action_ref/unref
[simgrid.git] / src / simdag / sd_task.c
index 63a95bc..3ce7e5b 100644 (file)
 #include "xbt/sysdep.h"
 #include "xbt/dynar.h"
 
 #include "xbt/sysdep.h"
 #include "xbt/dynar.h"
 
-/* Creates a task.
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(sd_task, sd,
+                                "Logging specific to SimDag (task)");
+
+static void __SD_task_remove_dependencies(SD_task_t task);
+static void __SD_task_destroy_scheduling_data(SD_task_t task);
+
+/**
+ * \brief Creates a new task.
+ *
+ * \param name the name of the task (can be \c NULL)
+ * \param data the user data you want to associate with the task (can be \c NULL)
+ * \param amount amount of the task
+ * \return the new task
+ * \see SD_task_destroy()
  */
  */
-SD_task_t SD_task_create(const char *name, void *data, double amount) {
+SD_task_t SD_task_create(const char *name, void *data, double amount)
+{
+
+  SD_task_t task;
   SD_CHECK_INIT_DONE();
   SD_CHECK_INIT_DONE();
-  xbt_assert0(amount > 0, "amount must be positive");
 
 
-  SD_task_data_t sd_data = xbt_new0(s_SD_task_data_t, 1); /* task private data */
+  task = xbt_new(s_SD_task_t, 1);
 
   /* general information */
 
   /* general information */
+  task->data = data;            /* user data */
   if (name != NULL)
   if (name != NULL)
-    sd_data->name = xbt_strdup(name);
+    task->name = xbt_strdup(name);
   else
   else
-    sd_data->name = NULL;
+    task->name = NULL;
+
+  task->state_hookup.prev = NULL;
+  task->state_hookup.next = NULL;
+  task->state_set = sd_global->not_scheduled_task_set;
+  task->state = SD_NOT_SCHEDULED;
+  xbt_swag_insert(task, task->state_set);
 
 
-  sd_data->state = SD_NOT_SCHEDULED;
-  sd_data->amount = amount;
-  sd_data->surf_action = NULL;
-  sd_data->watch_points = 0;
+  task->amount = amount;
+  task->remains = amount;
+  task->start_time = -1.0;
+  task->finish_time = -1.0;
+  task->surf_action = NULL;
+  task->watch_points = 0;
 
   /* dependencies */
 
   /* dependencies */
-  sd_data->tasks_before = xbt_dynar_new(sizeof(SD_dependency_t), NULL);
-  sd_data->tasks_after = xbt_dynar_new(sizeof(SD_dependency_t), NULL);
+  task->tasks_before = xbt_dynar_new(sizeof(SD_dependency_t), NULL);
+  task->tasks_after = xbt_dynar_new(sizeof(SD_dependency_t), NULL);
 
   /* scheduling parameters */
 
   /* scheduling parameters */
-  sd_data->workstation_nb = 0;
-  sd_data->workstation_list = NULL;
-  sd_data->computation_amount = NULL;
-  sd_data->communication_amount = NULL;
-  sd_data->rate = 0;
+  task->workstation_nb = 0;
+  task->workstation_list = NULL;
+  task->computation_amount = NULL;
+  task->communication_amount = NULL;
+  task->rate = 0;
 
 
-  SD_task_t task = xbt_new0(s_SD_task_t, 1);
-  task->sd_data = sd_data; /* private data */
-  task->data = data; /* user data */
+  sd_global->task_number++;
 
   return task;
 }
 
 
   return task;
 }
 
-/* Schedules a task.
- * task: the task to schedule
- * workstation_nb: number of workstations where the task will be executed
- * workstation_list: workstations where the task will be executed
- * computation_amount: computation amount for each workstation
- * communication_amount: communication amount between each pair of workstations
- * rate: task execution speed rate
+/**
+ * \brief Returns the user data of a task
+ *
+ * \param task a task
+ * \return the user data associated with this task (can be \c NULL)
+ * \see SD_task_set_data()
  */
  */
-void SD_task_schedule(SD_task_t task, int workstation_nb,
-                    const SD_workstation_t *workstation_list, double *computation_amount,
-                    double *communication_amount, double rate) {
+void *SD_task_get_data(SD_task_t task)
+{
   SD_CHECK_INIT_DONE();
   SD_CHECK_INIT_DONE();
-  xbt_assert0(task, "Invalid parameter");
-  xbt_assert1(SD_task_get_state(task) == SD_NOT_SCHEDULED, "Task '%s' has already been scheduled.", SD_task_get_name(task));
-  xbt_assert0(workstation_nb > 0, "workstation_nb must be positive");
-
-  SD_task_data_t sd_data = task->sd_data;
-  sd_data->workstation_nb = workstation_nb;
-  sd_data->rate = rate;
-
-  sd_data->computation_amount = xbt_new0(double, workstation_nb);
-  memcpy(sd_data->computation_amount, computation_amount, sizeof(double) * workstation_nb);
-
-  int communication_nb = workstation_nb * workstation_nb;
-  sd_data->communication_amount = xbt_new0(double, communication_nb);
-  memcpy(sd_data->communication_amount, communication_amount, sizeof(double) * communication_nb);
-
-  /* we have to create a Surf workstation array instead of the SimDag workstation array */
-  sd_data->workstation_list = xbt_new0(void*, workstation_nb);
-  int i;
-  for (i = 0; i < workstation_nb; i++) {
-    sd_data->workstation_list[i] = workstation_list[i]->sd_data->surf_workstation;
-  }
-
-  sd_data->state = SD_SCHEDULED;
+  xbt_assert0(task != NULL, "Invalid parameter");
+  return task->data;
 }
 
 }
 
-/* Returns the data of a task.
+/**
+ * \brief Sets the user data of a task
+ *
+ * The new data can be \c NULL. The old data should have been freed first
+ * if it was not \c NULL.
+ *
+ * \param task a task
+ * \param data the new data you want to associate with this task
+ * \see SD_task_get_data()
  */
  */
-void* SD_task_get_data(SD_task_t task) {
+void SD_task_set_data(SD_task_t task, void *data)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  return task->data;
+  task->data = data;
 }
 
 }
 
-/* Sets the data of a task.
+/**
+ * \brief Returns the state of a task
+ *
+ * \param task a task
+ * \return the current \ref e_SD_task_state_t "state" of this task:
+ * #SD_NOT_SCHEDULED, #SD_SCHEDULED, #SD_READY, #SD_RUNNING, #SD_DONE or #SD_FAILED
+ * \see e_SD_task_state_t
  */
  */
-void SD_task_set_data(SD_task_t task, void *data) {
+e_SD_task_state_t SD_task_get_state(SD_task_t task)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  task->data = data;
+  return task->state;
 }
 
 }
 
-/* Returns the name of a task. The name can be NULL.
+/* Changes the state of a task. Updates the swags and the flag sd_global->watch_point_reached.
  */
  */
-const char* SD_task_get_name(SD_task_t task) {
+void __SD_task_set_state(SD_task_t task, e_SD_task_state_t new_state)
+{
+  xbt_swag_remove(task, task->state_set);
+  switch (new_state) {
+  case SD_NOT_SCHEDULED:
+    task->state_set = sd_global->not_scheduled_task_set;
+    break;
+  case SD_SCHEDULED:
+    task->state_set = sd_global->scheduled_task_set;
+    break;
+  case SD_READY:
+    task->state_set = sd_global->ready_task_set;
+    break;
+  case SD_IN_FIFO:
+    task->state_set = sd_global->in_fifo_task_set;
+    break;
+  case SD_RUNNING:
+    task->state_set = sd_global->running_task_set;
+    task->start_time =
+      surf_workstation_model->action_get_start_time(task->surf_action);
+    break;
+  case SD_DONE:
+    task->state_set = sd_global->done_task_set;
+    task->finish_time =
+      surf_workstation_model->action_get_finish_time(task->surf_action);
+    task->remains = 0;
+    break;
+  case SD_FAILED:
+    task->state_set = sd_global->failed_task_set;
+    break;
+  default:
+    xbt_assert0(0, "Invalid state");
+  }
+  xbt_swag_insert(task, task->state_set);
+  task->state = new_state;
+
+  if (task->watch_points & new_state) {
+    INFO1("Watch point reached with task '%s'!", SD_task_get_name(task));
+    sd_global->watch_point_reached = 1;
+    SD_task_unwatch(task, new_state);   /* remove the watch point */
+  }
+}
+
+/**
+ * \brief Returns the name of a task
+ *
+ * \param task a task
+ * \return the name of this task (can be \c NULL)
+ */
+const char *SD_task_get_name(SD_task_t task)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  return task->sd_data->name;
+  return task->name;
 }
 
 }
 
-/* Returns the computing amount of a task.
+/**
+ * \brief Returns the total amount of a task
+ *
+ * \param task a task
+ * \return the total amount of this task
+ * \see SD_task_get_remaining_amount()
  */
  */
-double SD_task_get_amount(SD_task_t task) {
+double SD_task_get_amount(SD_task_t task)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  return task->sd_data->amount;
+  return task->amount;
 }
 
 }
 
-/* Returns the remaining computing amount of a task.
+/**
+ * \brief Returns the remaining amount of a task
+ *
+ * \param task a task
+ * \return the remaining amount of this task
+ * \see SD_task_get_amount()
  */
  */
-double SD_task_get_remaining_amount(SD_task_t task) {
+double SD_task_get_remaining_amount(SD_task_t task)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  SD_task_data_t sd_data = task->sd_data;
-  if (sd_data->surf_action)
-    return sd_data->amount;
+
+  if (task->surf_action)
+    return task->surf_action->remains;
   else
   else
-    return sd_data->surf_action->remains;
+    return task->remains;
 }
 
 /* temporary function for debbuging */
 }
 
 /* temporary function for debbuging */
-void __SD_print_dependencies(SD_task_t task) {
-  printf("The following tasks must be executed before %s:", SD_task_get_name(task));
-  xbt_dynar_t dynar = task->sd_data->tasks_before;
-  int length = xbt_dynar_length(dynar);
+static void __SD_print_dependencies(SD_task_t task)
+{
+  xbt_dynar_t dynar;
+  int length;
   int i;
   SD_dependency_t dependency;
   int i;
   SD_dependency_t dependency;
+
+  INFO1("The following tasks must be executed before %s:",
+        SD_task_get_name(task));
+  dynar = task->tasks_before;
+  length = xbt_dynar_length(dynar);
+
+
   for (i = 0; i < length; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
   for (i = 0; i < length; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
-    printf(" %s", SD_task_get_name(dependency->src));
+    INFO1(" %s", SD_task_get_name(dependency->src));
   }
 
   }
 
-  printf("\nThe following tasks must be executed after %s:", SD_task_get_name(task));
+  INFO1("The following tasks must be executed after %s:",
+        SD_task_get_name(task));
 
 
-  dynar = task->sd_data->tasks_after;
+  dynar = task->tasks_after;
   length = xbt_dynar_length(dynar);
   for (i = 0; i < length; i++) {
   length = xbt_dynar_length(dynar);
   for (i = 0; i < length; i++) {
-    xbt_dynar_get_ptr(dynar, i, &dependency);
-    printf(" %s", SD_task_get_name(dependency->dst));
+    xbt_dynar_get_cpy(dynar, i, &dependency);
+    INFO1(" %s", SD_task_get_name(dependency->dst));
   }
   }
-  printf("\n----------------------------\n");
+  INFO0("----------------------------");
 }
 
 }
 
-/* Adds a dependency between two tasks.
+/* Destroys a dependency between two tasks.
  */
  */
-void SD_task_dependency_add(const char *name, void *data, SD_task_t src, SD_task_t dst) {
-  SD_CHECK_INIT_DONE();
-  xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
-  xbt_assert1(src != dst, "Cannot add a dependency between task '%s' and itself", SD_task_get_name(src));
+static void __SD_task_dependency_destroy(void *dependency)
+{
+  if (((SD_dependency_t) dependency)->name != NULL)
+    xbt_free(((SD_dependency_t) dependency)->name);
+  xbt_free(dependency);
+}
 
 
-  xbt_dynar_t dynar = src->sd_data->tasks_after;
-  int length = xbt_dynar_length(dynar);
+/**
+ * \brief Adds a dependency between two tasks
+ *
+ * \a dst will depend on \a src, ie \a dst will not start before \a src is finished.
+ * Their \ref e_SD_task_state_t "state" must be #SD_NOT_SCHEDULED, #SD_SCHEDULED or #SD_READY.
+ *
+ * \param name the name of the new dependency (can be \c NULL)
+ * \param data the user data you want to associate with this dependency (can be \c NULL)
+ * \param src the task which must be executed first
+ * \param dst the task you want to make depend on \a src
+ * \see SD_task_dependency_remove()
+ */
+void SD_task_dependency_add(const char *name, void *data, SD_task_t src,
+                            SD_task_t dst)
+{
+  xbt_dynar_t dynar;
+  int length;
   int found = 0;
   int i;
   SD_dependency_t dependency;
   int found = 0;
   int i;
   SD_dependency_t dependency;
+
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
+
+  dynar = src->tasks_after;
+  length = xbt_dynar_length(dynar);
+
+
+
+  if (src == dst)
+    THROW1(arg_error, 0,
+           "Cannot add a dependency between task '%s' and itself",
+           SD_task_get_name(src));
+
+  if (!__SD_task_is_not_scheduled(src)
+      && !__SD_task_is_scheduled_or_ready(src))
+    THROW1(arg_error, 0,
+           "Task '%s' must be SD_NOT_SCHEDULED, SD_SCHEDULED or SD_READY",
+           SD_task_get_name(src));
+
+  if (!__SD_task_is_not_scheduled(dst)
+      && !__SD_task_is_scheduled_or_ready(dst))
+    THROW1(arg_error, 0,
+           "Task '%s' must be SD_NOT_SCHEDULED, SD_SCHEDULED or SD_READY",
+           SD_task_get_name(dst));
+
+  DEBUG2("SD_task_dependency_add: src = %s, dst = %s", SD_task_get_name(src),
+         SD_task_get_name(dst));
   for (i = 0; i < length && !found; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
   for (i = 0; i < length && !found; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
-    if (dependency->src == src && dependency->dst == dst) {
-      found = 1;
-    }
+    found = (dependency->dst == dst);
+    DEBUG2("Dependency %d: dependency->dst = %s", i,
+           SD_task_get_name(dependency->dst));
   }
   }
-  xbt_assert2(!found, "A dependency already exists between task '%s' and task '%s'", src->sd_data->name, dst->sd_data->name);
 
 
-  dependency = xbt_new0(s_SD_dependency_t, 1);
+  if (found)
+    THROW2(arg_error, 0,
+           "A dependency already exists between task '%s' and task '%s'",
+           SD_task_get_name(src), SD_task_get_name(dst));
+
+  dependency = xbt_new(s_SD_dependency_t, 1);
 
   if (name != NULL)
     dependency->name = xbt_strdup(name);
 
   if (name != NULL)
     dependency->name = xbt_strdup(name);
+  else
+    dependency->name = NULL;
+
   dependency->data = data;
   dependency->src = src;
   dependency->dst = dst;
 
   /* src must be executed before dst */
   dependency->data = data;
   dependency->src = src;
   dependency->dst = dst;
 
   /* src must be executed before dst */
-  xbt_dynar_push(src->sd_data->tasks_after, &dependency);
-  xbt_dynar_push(dst->sd_data->tasks_before, &dependency);
+  xbt_dynar_push(src->tasks_after, &dependency);
+  xbt_dynar_push(dst->tasks_before, &dependency);
+
+  /* if the task was ready, then dst->tasks_before is not empty anymore,
+     so we must go back to state SD_SCHEDULED */
+  if (__SD_task_is_ready(dst)) {
+    DEBUG1("SD_task_dependency_add: %s was ready and becomes scheduled!",
+           SD_task_get_name(dst));
+    __SD_task_set_state(dst, SD_SCHEDULED);
+  }
 
   /*  __SD_print_dependencies(src);
 
   /*  __SD_print_dependencies(src);
-      __SD_print_dependencies(dst);*/
+     __SD_print_dependencies(dst); */
 }
 
 }
 
-/* Removes a dependency between two tasks.
+/**
+ * \brief Indacates whether there is a dependency between two tasks.
+ *
+ * \param src a task
+ * \param dst a task depending on \a src
  */
  */
-void SD_task_dependency_remove(SD_task_t src, SD_task_t dst) {
+int SD_task_dependency_exists(SD_task_t src, SD_task_t dst)
+{
+  xbt_dynar_t dynar;
+  int length;
+  int i;
+  SD_dependency_t dependency;
+
   SD_CHECK_INIT_DONE();
   xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
-  xbt_assert1(src != dst, "Cannot remove a dependency between task '%s' and itself", SD_task_get_name(src));
 
 
-  xbt_dynar_t dynar = src->sd_data->tasks_after;
-  int length = xbt_dynar_length(dynar);
+  dynar = src->tasks_after;
+  length = xbt_dynar_length(dynar);
+
+  for (i = 0; i < length; i++) {
+    xbt_dynar_get_cpy(dynar, i, &dependency);
+    if (dependency->dst == dst)
+      return 1;
+  }
+  return 0;
+}
+
+/**
+ * \brief Remove a dependency between two tasks
+ *
+ * \param src a task
+ * \param dst a task depending on \a src
+ * \see SD_task_dependency_add()
+ */
+void SD_task_dependency_remove(SD_task_t src, SD_task_t dst)
+{
+
+  xbt_dynar_t dynar;
+  int length;
   int found = 0;
   int i;
   SD_dependency_t dependency;
   int found = 0;
   int i;
   SD_dependency_t dependency;
+
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
+
+  /* remove the dependency from src->tasks_after */
+  dynar = src->tasks_after;
+  length = xbt_dynar_length(dynar);
+
   for (i = 0; i < length && !found; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
   for (i = 0; i < length && !found; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
-    if (dependency->src == src && dependency->dst == dst) {
+    if (dependency->dst == dst) {
       xbt_dynar_remove_at(dynar, i, NULL);
       found = 1;
     }
   }
       xbt_dynar_remove_at(dynar, i, NULL);
       found = 1;
     }
   }
-  xbt_assert4(found, "No dependency found between task '%s' and '%s': task '%s' is not a successor of task '%s'",
-             src->sd_data->name, dst->sd_data->name, dst->sd_data->name, src->sd_data->name);
+  if (!found)
+    THROW4(arg_error, 0,
+           "No dependency found between task '%s' and '%s': task '%s' is not a successor of task '%s'",
+           SD_task_get_name(src), SD_task_get_name(dst),
+           SD_task_get_name(dst), SD_task_get_name(src));
 
 
-  dynar = dst->sd_data->tasks_before;
+  /* remove the dependency from dst->tasks_before */
+  dynar = dst->tasks_before;
   length = xbt_dynar_length(dynar);
   found = 0;
   length = xbt_dynar_length(dynar);
   found = 0;
-  
+
   for (i = 0; i < length && !found; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
   for (i = 0; i < length && !found; i++) {
     xbt_dynar_get_cpy(dynar, i, &dependency);
-    if (dependency->src == src && dependency->dst == dst) {
+    if (dependency->src == src) {
       xbt_dynar_remove_at(dynar, i, NULL);
       xbt_dynar_remove_at(dynar, i, NULL);
-      __SD_task_destroy_dependency(dependency);
+      __SD_task_dependency_destroy(dependency);
       found = 1;
     }
   }
       found = 1;
     }
   }
-  xbt_assert4(found, "SimDag error: task '%s' is a successor of '%s' but task '%s' is not a predecessor of task '%s'",
-             dst->sd_data->name, src->sd_data->name, src->sd_data->name, dst->sd_data->name); /* should never happen... */
+  /* should never happen... */
+  xbt_assert4(found,
+              "SimDag error: task '%s' is a successor of '%s' but task '%s' is not a predecessor of task '%s'",
+              SD_task_get_name(dst), SD_task_get_name(src),
+              SD_task_get_name(src), SD_task_get_name(dst));
+
+  /* if the task was scheduled and dst->tasks_before is empty now, we can make it ready */
+  if (xbt_dynar_length(dst->tasks_before) == 0 && __SD_task_is_scheduled(dst))
+    __SD_task_set_state(dst, SD_READY);
 
   /*  __SD_print_dependencies(src);
 
   /*  __SD_print_dependencies(src);
-      __SD_print_dependencies(dst);*/
+     __SD_print_dependencies(dst); */
 }
 
 }
 
-/* Returns the state of a task: SD_NOT_SCHEDULED, SD_SCHEDULED, SD_RUNNING, SD_DONE or SD_FAILED.
+/**
+ * \brief Returns the user data associated with a dependency between two tasks
+ *
+ * \param src a task
+ * \param dst a task depending on \a src
+ * \return the user data associated with this dependency (can be \c NULL)
+ * \see SD_task_dependency_add()
  */
  */
-SD_task_state_t SD_task_get_state(SD_task_t task) {
+void *SD_task_dependency_get_data(SD_task_t src, SD_task_t dst)
+{
+
+  xbt_dynar_t dynar;
+  int length;
+  int found = 0;
+  int i;
+  SD_dependency_t dependency;
+
+
   SD_CHECK_INIT_DONE();
   SD_CHECK_INIT_DONE();
-  xbt_assert0(task != NULL, "Invalid parameter");
-  return task->sd_data->state;
+  xbt_assert0(src != NULL && dst != NULL, "Invalid parameter");
+
+  dynar = src->tasks_after;
+  length = xbt_dynar_length(dynar);
+
+  for (i = 0; i < length && !found; i++) {
+    xbt_dynar_get_cpy(dynar, i, &dependency);
+    found = (dependency->dst == dst);
+  }
+  if (!found)
+    THROW2(arg_error, 0, "No dependency found between task '%s' and '%s'",
+           SD_task_get_name(src), SD_task_get_name(dst));
+  return dependency->data;
 }
 
 /* temporary function for debugging */
 }
 
 /* temporary function for debugging */
-void __SD_print_watch_points(SD_task_t task) {
-  static const int state_masks[] = {SD_SCHEDULED, SD_RUNNING, SD_DONE, SD_FAILED};
-  static const char* state_names[] = {"scheduled", "running", "done", "failed"};
+static void __SD_print_watch_points(SD_task_t task)
+{
+  static const int state_masks[] =
+    { SD_SCHEDULED, SD_RUNNING, SD_READY, SD_DONE, SD_FAILED };
+  static const char *state_names[] =
+    { "scheduled", "running", "ready", "done", "failed" };
+  int i;
 
 
-  printf("Task '%s' watch points (%x): ", task->sd_data->name, task->sd_data->watch_points);
+  INFO2("Task '%s' watch points (%x): ", SD_task_get_name(task),
+        task->watch_points);
 
 
-  int i;
-  for (i = 0; i < 4; i++) {
-    if (task->sd_data->watch_points & state_masks[i])
-      printf("%s ", state_names[i]);
+
+  for (i = 0; i < 5; i++) {
+    if (task->watch_points & state_masks[i])
+      INFO1("%s ", state_names[i]);
   }
   }
-  printf("\n");
 }
 
 }
 
-/* Adds a watch point to a task.
-   SD_simulate will stop as soon as the state of this task is the one given in argument.
-   Watch point is then automatically removed.
+/**
+ * \brief Adds a watch point to a task
+ *
+ * SD_simulate() will stop as soon as the \ref e_SD_task_state_t "state" of this
+ * task becomes the one given in argument. The
+ * watch point is then automatically removed.
+ *
+ * \param task a task
+ * \param state the \ref e_SD_task_state_t "state" you want to watch
+ * (cannot be #SD_NOT_SCHEDULED)
+ * \see SD_task_unwatch()
  */
  */
-void SD_task_watch(SD_task_t task, SD_task_state_t state) {
+void SD_task_watch(SD_task_t task, e_SD_task_state_t state)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
 
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
 
-  task->sd_data->watch_points = task->sd_data->watch_points | state;
-  __SD_print_watch_points(task);
+  if (state & SD_NOT_SCHEDULED)
+    THROW0(arg_error, 0,
+           "Cannot add a watch point for state SD_NOT_SCHEDULED");
+
+  task->watch_points = task->watch_points | state;
+  /*  __SD_print_watch_points(task); */
 }
 
 }
 
-/* Removes a watch point from a task.
+/**
+ * \brief Removes a watch point from a task
+ *
+ * \param task a task
+ * \param state the \ref e_SD_task_state_t "state" you no longer want to watch
+ * \see SD_task_watch()
  */
  */
-void SD_task_unwatch(SD_task_t task, SD_task_state_t state) {
+void SD_task_unwatch(SD_task_t task, e_SD_task_state_t state)
+{
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  
-  task->sd_data->watch_points = task->sd_data->watch_points & ~state;
-  __SD_print_watch_points(task);
+  xbt_assert0(state != SD_NOT_SCHEDULED,
+              "SimDag error: Cannot have a watch point for state SD_NOT_SCHEDULED");
+
+  task->watch_points = task->watch_points & ~state;
+  /*  __SD_print_watch_points(task); */
 }
 
 }
 
-/* Unschedules a task. The state must be SD_SCHEDULED, SD_RUNNING or SD_FAILED.
- * The task is reinitialised and its state becomes SD_NOT_SCHEDULED.
- * Call SD_task_schedule to schedule it again.
+/**
+ * \brief Returns an approximative estimation of the execution time of a task.
+ *
+ * The estimation is very approximative because the value returned is the time
+ * the task would take if it was executed now and if it was the only task.
+ *
+ * \param task the task to evaluate
+ * \param workstation_nb number of workstations on which the task would be executed
+ * \param workstation_list the workstations on which the task would be executed
+ * \param computation_amount computation amount for each workstation
+ * \param communication_amount communication amount between each pair of workstations
+ * \param rate task execution speed rate
+ * \see SD_schedule()
  */
  */
-void SD_task_unschedule(SD_task_t task) {
+double SD_task_get_execution_time(SD_task_t task,
+                                  int workstation_nb,
+                                  const SD_workstation_t * workstation_list,
+                                  const double *computation_amount,
+                                  const double *communication_amount,
+                                  double rate)
+{
+  double time, max_time = 0.0;
+  int i, j;
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(task != NULL && workstation_nb > 0 && workstation_list != NULL
+              && computation_amount != NULL
+              && communication_amount != NULL, "Invalid parameter");
+
+  /* the task execution time is the maximum execution time of the parallel tasks */
+
+  for (i = 0; i < workstation_nb; i++) {
+    time =
+      SD_workstation_get_computation_time(workstation_list[i],
+                                          computation_amount[i]);
+
+    for (j = 0; j < workstation_nb; j++) {
+      time +=
+        SD_route_get_communication_time(workstation_list[i],
+                                        workstation_list[j],
+                                        communication_amount[i *
+                                                             workstation_nb +
+                                                             j]);
+    }
+
+    if (time > max_time) {
+      max_time = time;
+    }
+  }
+  return max_time * SD_task_get_amount(task);
+}
+
+/**
+ * \brief Schedules a task
+ *
+ * The task state must be #SD_NOT_SCHEDULED.
+ * Once scheduled, a task will be executed as soon as possible in SD_simulate(),
+ * i.e. when its dependencies are satisfied.
+ *
+ * \param task the task you want to schedule
+ * \param workstation_nb number of workstations on which the task will be executed
+ * \param workstation_list the workstations on which the task will be executed
+ * \param computation_amount computation amount for each workstation
+ * \param communication_amount communication amount between each pair of workstations
+ * \param rate task execution speed rate
+ * \see SD_task_unschedule()
+ */
+void SD_task_schedule(SD_task_t task, int workstation_nb,
+                      const SD_workstation_t * workstation_list,
+                      const double *computation_amount,
+                      const double *communication_amount, double rate)
+{
+
+  int communication_nb;
+
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
-  xbt_assert1(task->sd_data->state == SD_SCHEDULED ||
-             task->sd_data->state == SD_RUNNING ||
-             task->sd_data->state == SD_FAILED,
-             "Task %s: the state must be SD_SCHEDULED, SD_RUNNING or SD_FAILED", task->sd_data->name);
+  xbt_assert0(workstation_nb > 0, "workstation_nb must be positive");
+
+  if (!__SD_task_is_not_scheduled(task))
+    THROW1(arg_error, 0, "Task '%s' has already been scheduled",
+           SD_task_get_name(task));
+
+  task->workstation_nb = workstation_nb;
+  task->rate = rate;
+
+  task->computation_amount = xbt_new(double, workstation_nb);
+  memcpy(task->computation_amount, computation_amount,
+         sizeof(double) * workstation_nb);
 
 
-  if (task->sd_data->state == SD_SCHEDULED)
+  communication_nb = workstation_nb * workstation_nb;
+  task->communication_amount = xbt_new(double, communication_nb);
+  memcpy(task->communication_amount, communication_amount,
+         sizeof(double) * communication_nb);
+
+  task->workstation_list = xbt_new(SD_workstation_t, workstation_nb);
+  memcpy(task->workstation_list, workstation_list,
+         sizeof(SD_workstation_t) * workstation_nb);
+
+  /* update the task state */
+  if (xbt_dynar_length(task->tasks_before) == 0)
+    __SD_task_set_state(task, SD_READY);
+  else
+    __SD_task_set_state(task, SD_SCHEDULED);
+}
+
+/**
+ * \brief Unschedules a task
+ *
+ * The task state must be #SD_SCHEDULED, #SD_READY, #SD_RUNNING or #SD_FAILED.
+ * If you call this function, the task state becomes #SD_NOT_SCHEDULED.
+ * Call SD_task_schedule() to schedule it again.
+ *
+ * \param task the task you want to unschedule
+ * \see SD_task_schedule()
+ */
+void SD_task_unschedule(SD_task_t task)
+{
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(task != NULL, "Invalid parameter");
+
+  if (task->state_set != sd_global->scheduled_task_set &&
+      task->state_set != sd_global->ready_task_set &&
+      task->state_set != sd_global->running_task_set &&
+      task->state_set != sd_global->failed_task_set)
+    THROW1(arg_error, 0,
+           "Task %s: the state must be SD_SCHEDULED, SD_READY, SD_RUNNING or SD_FAILED",
+           SD_task_get_name(task));
+
+  if (__SD_task_is_scheduled_or_ready(task))    /* if the task is scheduled or ready */
     __SD_task_destroy_scheduling_data(task);
 
     __SD_task_destroy_scheduling_data(task);
 
-  task->sd_data->state = SD_NOT_SCHEDULED;
+  if (__SD_task_is_running(task))       /* the task should become SD_FAILED */
+    surf_workstation_model->action_cancel(task->surf_action);
+  else
+    __SD_task_set_state(task, SD_NOT_SCHEDULED);
+  task->remains = task->amount;
+  task->start_time = -1.0;
 }
 
 }
 
-/* Runs a task. This function is called by SD_simulate when a scheduled task can start
- * (ie when its dependencies are satisfied).
+/* Destroys the data memorised by SD_task_schedule. Task state must be SD_SCHEDULED or SD_READY.
  */
  */
-void __SD_task_run(SD_task_t task) {
+static void __SD_task_destroy_scheduling_data(SD_task_t task)
+{
+  SD_CHECK_INIT_DONE();
+  if (!__SD_task_is_scheduled_or_ready(task) && !__SD_task_is_in_fifo(task))
+    THROW1(arg_error, 0,
+           "Task '%s' must be SD_SCHEDULED, SD_READY or SD_IN_FIFO",
+           SD_task_get_name(task));
+
+  xbt_free(task->computation_amount);
+  xbt_free(task->communication_amount);
+}
+
+/* Runs a task. This function is directly called by __SD_task_try_to_run if the task
+ * doesn't have to wait in fifos. Otherwise, it is called by __SD_task_just_done when
+ * the task gets out of its fifos.
+ */
+void __SD_task_really_run(SD_task_t task)
+{
+
+  int i;
+  void **surf_workstations;
+
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
+  xbt_assert2(__SD_task_is_ready_or_in_fifo(task),
+              "Task '%s' is not ready or in a fifo! Task state: %d",
+              SD_task_get_name(task), SD_task_get_state(task));
+  xbt_assert1(task->workstation_list != NULL,
+              "Task '%s': workstation_list is NULL!", SD_task_get_name(task));
+
+
+
+  DEBUG1("Really running task '%s'", SD_task_get_name(task));
+
+  /* set this task as current task for the workstations in sequential mode */
+  for (i = 0; i < task->workstation_nb; i++) {
+    if (SD_workstation_get_access_mode(task->workstation_list[i]) ==
+        SD_WORKSTATION_SEQUENTIAL_ACCESS) {
+      task->workstation_list[i]->current_task = task;
+      xbt_assert0(__SD_workstation_is_busy(task->workstation_list[i]),
+                  "The workstation should be busy now");
+    }
+  }
+
+  DEBUG1("Task '%s' set as current task for its workstations",
+         SD_task_get_name(task));
+
+  /* start the task */
+
+  /* we have to create a Surf workstation array instead of the SimDag workstation array */
+  surf_workstations = xbt_new(void *, task->workstation_nb);
+
+  for (i = 0; i < task->workstation_nb; i++) {
+    surf_workstations[i] = task->workstation_list[i]->surf_workstation;
+  }
+
+  task->surf_action = NULL;
+  if ((task->workstation_nb == 1) && (task->communication_amount[0] == 0.0)) {
+    task->surf_action =
+      surf_workstation_model->extension.workstation.
+      execute(surf_workstations[0], task->computation_amount[0]);
+  } else if ((task->workstation_nb == 1)
+             && (task->computation_amount[0] == 0.0)) {
+    task->surf_action =
+      surf_workstation_model->extension.workstation.
+      communicate(surf_workstations[0], surf_workstations[0],
+                  task->communication_amount[0], task->rate);
+  } else if ((task->workstation_nb == 2)
+             && (task->computation_amount[0] == 0.0)
+             && (task->computation_amount[1] == 0.0)) {
+    int nb = 0;
+    double value = 0.0;
+
+    for (i = 0; i < task->workstation_nb * task->workstation_nb; i++) {
+      if (task->communication_amount[i] > 0.0) {
+        nb++;
+        value = task->communication_amount[i];
+      }
+    }
+    if (nb == 1) {
+      task->surf_action =
+        surf_workstation_model->extension.workstation.
+        communicate(surf_workstations[0], surf_workstations[1], value,
+                    task->rate);
+    }
+  }
+  if (!task->surf_action) {
+    double *computation_amount = xbt_new(double, task->workstation_nb);
+    double *communication_amount = xbt_new(double, task->workstation_nb *
+                                           task->workstation_nb);
+
+    memcpy(computation_amount, task->computation_amount, sizeof(double) *
+           task->workstation_nb);
+    memcpy(communication_amount, task->communication_amount,
+           sizeof(double) * task->workstation_nb * task->workstation_nb);
+
+    task->surf_action =
+      surf_workstation_model->extension.workstation.
+      execute_parallel_task(task->workstation_nb, surf_workstations,
+                            computation_amount, communication_amount,
+                            task->amount, task->rate);
+  } else {
+    xbt_free(surf_workstations);
+  }
+
+  surf_workstation_model->action_data_set(task->surf_action, task);
+
+  DEBUG1("surf_action = %p", task->surf_action);
+
+  __SD_task_destroy_scheduling_data(task);      /* now the scheduling data are not useful anymore */
+  __SD_task_set_state(task, SD_RUNNING);
+  xbt_assert2(__SD_task_is_running(task), "Bad state of task '%s': %d",
+              SD_task_get_name(task), SD_task_get_state(task));
 
 
-  SD_task_data_t sd_data = task->sd_data;
-  surf_workstation_resource->extension_public->
-    execute_parallel_task(sd_data->workstation_nb,
-                         sd_data->workstation_list,
-                         sd_data->computation_amount,
-                         sd_data->communication_amount,
-                         sd_data->amount,
-                         sd_data->rate);
-  task->sd_data->state = SD_RUNNING;
-
-  __SD_task_destroy_scheduling_data(task); /* now the scheduling data are not useful anymore */
 }
 
 }
 
+/* Tries to run a task. This function is called by SD_simulate() when a scheduled task becomes SD_READY
+ * (ie when its dependencies are satisfied).
+ * If one of the workstations where the task is scheduled on is busy (in sequential mode),
+ * the task doesn't start.
+ * Returns whether the task has started.
+ */
+int __SD_task_try_to_run(SD_task_t task)
+{
 
 
-/* Destroys a task. The user data (if any) should have been destroyed first.
+  int can_start = 1;
+  int i;
+  SD_workstation_t workstation;
+
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(task != NULL, "Invalid parameter");
+  xbt_assert2(__SD_task_is_ready(task),
+              "Task '%s' is not ready! Task state: %d",
+              SD_task_get_name(task), SD_task_get_state(task));
+
+
+  for (i = 0; i < task->workstation_nb; i++) {
+    can_start = !__SD_workstation_is_busy(task->workstation_list[i]);
+  }
+
+  DEBUG2("Task '%s' can start: %d", SD_task_get_name(task), can_start);
+
+  if (!can_start) {             /* if the task cannot start and is not in the fifos yet */
+    for (i = 0; i < task->workstation_nb; i++) {
+      workstation = task->workstation_list[i];
+      if (workstation->access_mode == SD_WORKSTATION_SEQUENTIAL_ACCESS) {
+        DEBUG2("Pushing task '%s' in the fifo of workstation '%s'",
+               SD_task_get_name(task), SD_workstation_get_name(workstation));
+        xbt_fifo_push(workstation->task_fifo, task);
+      }
+    }
+    __SD_task_set_state(task, SD_IN_FIFO);
+    xbt_assert2(__SD_task_is_in_fifo(task), "Bad state of task '%s': %d",
+                SD_task_get_name(task), SD_task_get_state(task));
+    DEBUG1("Task '%s' state is now SD_IN_FIFO", SD_task_get_name(task));
+  } else {
+    __SD_task_really_run(task);
+  }
+
+  return can_start;
+}
+
+/* This function is called by SD_simulate when a task is done.
+ * It updates task->state and task->action and executes if necessary the tasks
+ * which were waiting in fifos for the end of `task'
  */
  */
-void SD_task_destroy(SD_task_t task) {
+void __SD_task_just_done(SD_task_t task)
+{
+  int i, j;
+  SD_workstation_t workstation;
+
+  SD_task_t candidate;
+  int candidate_nb = 0;
+  int candidate_capacity = 8;
+  SD_task_t *candidates;
+  int can_start = 1;
+
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
   SD_CHECK_INIT_DONE();
   xbt_assert0(task != NULL, "Invalid parameter");
+  xbt_assert1(__SD_task_is_running(task),
+              "The task must be running! Task state: %d",
+              SD_task_get_state(task));
+  xbt_assert1(task->workstation_list != NULL,
+              "Task '%s': workstation_list is NULL!", SD_task_get_name(task));
+
 
 
-  /*  printf("Destroying task %s...\n", SD_task_get_name(task));*/
+  candidates = xbt_new(SD_task_t, 8);
 
 
+  __SD_task_set_state(task, SD_DONE);
+  surf_workstation_model->action_unref(task->surf_action);
+  task->surf_action = NULL;
+
+  DEBUG0("Looking for candidates");
+
+  /* if the task was executed on sequential workstations,
+     maybe we can execute the next task of the fifo for each workstation */
+  for (i = 0; i < task->workstation_nb; i++) {
+    workstation = task->workstation_list[i];
+    DEBUG2("Workstation '%s': access_mode = %d",
+           SD_workstation_get_name(workstation), workstation->access_mode);
+    if (workstation->access_mode == SD_WORKSTATION_SEQUENTIAL_ACCESS) {
+      xbt_assert1(workstation->task_fifo != NULL,
+                  "Workstation '%s' has sequential access but no fifo!",
+                  SD_workstation_get_name(workstation));
+      xbt_assert2(workstation->current_task =
+                  task, "Workstation '%s': current task should be '%s'",
+                  SD_workstation_get_name(workstation),
+                  SD_task_get_name(task));
+
+      /* the task is over so we can release the workstation */
+      workstation->current_task = NULL;
+
+      DEBUG0("Getting candidate in fifo");
+      candidate =
+        xbt_fifo_get_item_content(xbt_fifo_get_first_item
+                                  (workstation->task_fifo));
+
+      if (candidate != NULL) {
+        DEBUG1("Candidate: '%s'", SD_task_get_name(candidate));
+        xbt_assert2(__SD_task_is_in_fifo(candidate),
+                    "Bad state of candidate '%s': %d",
+                    SD_task_get_name(candidate),
+                    SD_task_get_state(candidate));
+      }
+
+      DEBUG1("Candidate in fifo: %p", candidate);
+
+      /* if there was a task waiting for my place */
+      if (candidate != NULL) {
+        /* Unfortunately, we are not sure yet that we can execute the task now,
+           because the task can be waiting more deeply in some other workstation's fifos...
+           So we memorize all candidate tasks, and then we will check for each candidate
+           whether or not all its workstations are available. */
+
+        /* realloc if necessary */
+        if (candidate_nb == candidate_capacity) {
+          candidate_capacity *= 2;
+          candidates =
+            xbt_realloc(candidates, sizeof(SD_task_t) * candidate_capacity);
+        }
+
+        /* register the candidate */
+        candidates[candidate_nb++] = candidate;
+        candidate->fifo_checked = 0;
+      }
+    }
+  }
+
+  DEBUG1("Candidates found: %d", candidate_nb);
+
+  /* now we check every candidate task */
+  for (i = 0; i < candidate_nb; i++) {
+    candidate = candidates[i];
+
+    if (candidate->fifo_checked) {
+      continue;                 /* we have already evaluated that task */
+    }
+
+    xbt_assert2(__SD_task_is_in_fifo(candidate),
+                "Bad state of candidate '%s': %d",
+                SD_task_get_name(candidate), SD_task_get_state(candidate));
+
+    for (j = 0; j < candidate->workstation_nb && can_start; j++) {
+      workstation = candidate->workstation_list[j];
+
+      /* I can start on this workstation if the workstation is shared
+         or if I am the first task in the fifo */
+      can_start = workstation->access_mode == SD_WORKSTATION_SHARED_ACCESS ||
+        candidate ==
+        xbt_fifo_get_item_content(xbt_fifo_get_first_item
+                                  (workstation->task_fifo));
+    }
+
+    DEBUG2("Candidate '%s' can start: %d", SD_task_get_name(candidate),
+           can_start);
+
+    /* now we are sure that I can start! */
+    if (can_start) {
+      for (j = 0; j < candidate->workstation_nb && can_start; j++) {
+        workstation = candidate->workstation_list[j];
+
+        /* update the fifo */
+        if (workstation->access_mode == SD_WORKSTATION_SEQUENTIAL_ACCESS) {
+          candidate = xbt_fifo_shift(workstation->task_fifo);   /* the return value is stored just for debugging */
+          DEBUG1("Head of the fifo: '%s'",
+                 (candidate != NULL) ? SD_task_get_name(candidate) : "NULL");
+          xbt_assert0(candidate == candidates[i],
+                      "Error in __SD_task_just_done: bad first task in the fifo");
+        }
+      }                         /* for each workstation */
+
+      /* finally execute the task */
+      DEBUG2("Task '%s' state: %d", SD_task_get_name(candidate),
+             SD_task_get_state(candidate));
+      __SD_task_really_run(candidate);
+
+      DEBUG4
+        ("Calling __SD_task_is_running: task '%s', state set: %p, running_task_set: %p, is running: %d",
+         SD_task_get_name(candidate), candidate->state_set,
+         sd_global->running_task_set, __SD_task_is_running(candidate));
+      xbt_assert2(__SD_task_is_running(candidate),
+                  "Bad state of task '%s': %d", SD_task_get_name(candidate),
+                  SD_task_get_state(candidate));
+      DEBUG0("Okay, the task is running.");
+
+    }                           /* can start */
+    candidate->fifo_checked = 1;
+  }                             /* for each candidate */
+
+  xbt_free(candidates);
+}
+
+/* Remove all dependencies associated with a task. This function is called when the task is destroyed.
+ */
+static void __SD_task_remove_dependencies(SD_task_t task)
+{
   /* we must destroy the dependencies carefuly (with SD_dependency_remove)
      because each one is stored twice */
   SD_dependency_t dependency;
   /* we must destroy the dependencies carefuly (with SD_dependency_remove)
      because each one is stored twice */
   SD_dependency_t dependency;
-  while (xbt_dynar_length(task->sd_data->tasks_before) > 0) {
-    xbt_dynar_get_cpy(task->sd_data->tasks_before, 0, &dependency);
+  while (xbt_dynar_length(task->tasks_before) > 0) {
+    xbt_dynar_get_cpy(task->tasks_before, 0, &dependency);
     SD_task_dependency_remove(dependency->src, dependency->dst);
   }
 
     SD_task_dependency_remove(dependency->src, dependency->dst);
   }
 
-  while (xbt_dynar_length(task->sd_data->tasks_after) > 0) {
-    xbt_dynar_get_cpy(task->sd_data->tasks_after, 0, &dependency);
+  while (xbt_dynar_length(task->tasks_after) > 0) {
+    xbt_dynar_get_cpy(task->tasks_after, 0, &dependency);
     SD_task_dependency_remove(dependency->src, dependency->dst);
   }
     SD_task_dependency_remove(dependency->src, dependency->dst);
   }
+}
 
 
-  if (task->sd_data->state == SD_SCHEDULED)
+/**
+ * \brief Returns the start time of a task
+ *
+ * The task state must be SD_RUNNING, SD_DONE or SD_FAILED.
+ *
+ * \param task: a task
+ * \return the start time of this task
+ */
+double SD_task_get_start_time(SD_task_t task)
+{
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(task != NULL, "Invalid parameter");
+  if (task->surf_action)
+    return surf_workstation_model->action_get_start_time(task->surf_action);
+  else
+    return task->start_time;
+}
+
+/**
+ * \brief Returns the finish time of a task
+ *
+ * The task state must be SD_RUNNING, SD_DONE or SD_FAILED.
+ * If the state is not completed yet, the returned value is an
+ * estimation of the task finish time. This value can fluctuate
+ * until the task is completed.
+ *
+ * \param task: a task
+ * \return the start time of this task
+ */
+double SD_task_get_finish_time(SD_task_t task)
+{
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(task != NULL, "Invalid parameter");
+
+  if (task->surf_action)        /* should never happen as actions are destroyed right after their completion */
+    return surf_workstation_model->action_get_finish_time(task->surf_action);
+  else
+    return task->finish_time;
+}
+
+/**
+ * \brief Destroys a task.
+ *
+ * The user data (if any) should have been destroyed first.
+ *
+ * \param task the task you want to destroy
+ * \see SD_task_create()
+ */
+void SD_task_destroy(SD_task_t task)
+{
+  SD_CHECK_INIT_DONE();
+  xbt_assert0(task != NULL, "Invalid parameter");
+
+  DEBUG1("Destroying task %s...", SD_task_get_name(task));
+
+  __SD_task_remove_dependencies(task);
+
+  /* if the task was scheduled or ready we have to free the scheduling parameters */
+  if (__SD_task_is_scheduled_or_ready(task))
     __SD_task_destroy_scheduling_data(task);
 
     __SD_task_destroy_scheduling_data(task);
 
-  if (task->sd_data->name != NULL)
-    xbt_free(task->sd_data->name);
+  if (task->name != NULL)
+    xbt_free(task->name);
 
 
-  xbt_dynar_free(&task->sd_data->tasks_before);
-  xbt_dynar_free(&task->sd_data->tasks_after);
-  xbt_free(task->sd_data);
-  xbt_free(task);
+  if (task->surf_action != NULL)
+    surf_workstation_model->action_unref(task->surf_action);
 
 
-  /*printf("Task destroyed.\n");*/
+  if (task->workstation_list != NULL)
+    xbt_free(task->workstation_list);
 
 
-}
+  xbt_dynar_free(&task->tasks_before);
+  xbt_dynar_free(&task->tasks_after);
+  xbt_free(task);
 
 
-/* Destroys the data memorised by SD_task_schedule. Task state must be SD_SCHEDULED.
- */
-void __SD_task_destroy_scheduling_data(SD_task_t task) {
-  xbt_free(task->sd_data->workstation_list);
-  xbt_free(task->sd_data->computation_amount);
-  xbt_free(task->sd_data->communication_amount);
-}
+  sd_global->task_number--;
 
 
-/* Destroys a dependency between two tasks.
- */
-void __SD_task_destroy_dependency(void *dependency) {
-  if (((SD_dependency_t) dependency)->name != NULL)
-    xbt_free(((SD_dependency_t) dependency)->name);
-  /*printf("destroying dependency between %s and %s\n", ((SD_dependency_t) dependency)->src->sd_data->name, ((SD_dependency_t) dependency)->dst->sd_data->name);*/
-  xbt_free(dependency);
-  /*printf("destroyed.\n");*/
+  DEBUG0("Task destroyed.");
 }
 }